Oxygen atom interactions with fused silica surfaces: 1D and 3P state-resolved energy transfer dynamics

Abstract

A laser-based O atom beam source together with state-resolved detection techniques are used to characterize the energy transfer dynamics of ground (3P) and electronically excited (1D) state O atoms interacting with a fused silica surface. Time-of-flight spectra of the incident beam and scattered O atoms are measured, and provide detailed information regarding state-resolved angular and velocity distributions. We find a significant degree of “thermalization” (angular, fine structure state, and velocity distributions) in the scattered O(3P) atoms. The survival probability of O(1D) is determined to be ⩽0.01, and the probability for O(1D) quenching to “super-elastic” O(3P) is 0.05. Given that the measured probability for radiative quenching of 1D is not significant (⩽0.001), these results indicate that the majority of the available energy in the incident O atoms (both 3P and 1D) is transferred to the substrate. The implications of the scattering/energy transfer dynamics with respect to the O atom/fused silica surface interactions are discussed.

Atomic oxygen reactions with semifluorinated and n-alkanethiolate self-assembled monolayers

“…For example, oxygen radical-surface collisions are a component of oxygen plasma treatments that are used to enhance adhesion 6 and biocompatibility. 7 Similarly, as a result of the importance of silicon oxidation and the use of oxygen plasmas in semiconductor processing, studies of AO reactions with clean silicon, 8 fused silica, 9 and hydrocarbon terminated Si͑100͒ surfaces 10 have also been reported.…”

Diffusion and Reactions of Photoinduced Interstitial Oxygen Atoms in Amorphous SiO2 Impregnated with 18O-Labeled Interstitial Oxygen Molecules

“…Vacuum-ultraviolet (VUV) light ( h ν ≳ 6.2 eV) efficiently decomposes interstitial O 2 in a -SiO 2 and generates interstitial O 0 . , Theoretical studies have shown that an interstitial O 0 in a -SiO 2 is readily incorporated into the Si–O–Si network to form a peroxy linkage (POL, Si–O–O–Si). − The presence of mobile O 0 in a -SiO 2 is indicated by the creation of interstitial O 2 through the radiolytic decomposition of regular Si–O–Si bonds (Frenkel process), − ,− the formation of interstitial ozone molecules (O 3 ), and the interconversion between oxygen dangling bonds (nonbridging oxygen hole center, NBOHC, SiO • ) and peroxy radicals (POR, SiOO • ) . Interactions between O 0 and the surfaces of a -SiO 2 have attracted attention because of their relevance for plasma processing and catalysis . However, isotope labeling, which is a powerful tool for investigating diffusion and reactions of chemical species, has not been used to study interstitial O 0 in a -SiO 2 .…”

“…5−11 The presence of mobile O 0 in a-SiO 2 is indicated by the creation of interstitial O 2 through the radiolytic decomposition of regular Si−O−Si bonds (Frenkel process), 5−7,12−17 the formation of interstitial ozone molecules (O 3 ), 18 and the interconversion between oxygen dangling bonds (nonbridging oxygen hole center, NBOHC, SiO • ) and peroxy radicals (POR, SiOO • ). 19 Interactions between O 0 and the surfaces of a-SiO 2 have attracted attention because of their relevance for plasma processing 20 and catalysis. 21 However, isotope labeling, which is a powerful tool for investigating diffusion and reactions of chemical species, has not been used to study interstitial O 0 in a-SiO 2 .…”